Combination tube form bend and inflation application

ABSTRACT

An apparatus for embossing and bending metal strip having a pattern of stop-weld material sandwiched within it, with at least a portion of the stop-weld material corresponding to at least one inflatable fluid passageway. The apparatus comprises a spindle whose operative surface is contoured to provide the desired bend radius. The apparatus further includes means for embossing the strip and means for bending the strip about the spindle. Alternative embodiments include the use of a rubber spindle and combined means for bending and embossing the strip.

United States Patent 51 3,690,140 Shive 51 Sept. 12, 1972 [54] COMBINATION TUBE FORM BEND 3,200,631 8/1965 Kritzer, Jr ..72/309 AND INFLATION APPLICATION 2,850,793 9/1958 Schweller ..29/157.3 [72] Inventor: Richard A. Shive, 422 Semng, 3,024,525 3/ 1962 Wisberger ..29/ 157.3

Madlsml, 62060 FOREIGN PATENTS OR APPLICATIONS [221 Fi1ed= 1971 733,209 7/1955 Great Britain ..72/319 [21] Appl. N0.: 111,691

Primary ExaminerCharles W. Lanham Related Appllcatlon Data Assistant Examiner-Michael J. Keenan [60] Continuation of Ser. No. 823,219, Feb. 25, Attorney-Henry W- Cummmgs, Robert Bachman 1969, abandoned, which is a division of Ser. and Rchard Smolder No. 709,636, March 1, 1968, Pat. No. 3,545,394. [57] ABSTRACT An apparatus for embossing and bending metal strip [52] U.S.Cl ..72/293,29/157.3 V, 113/118 D having a pattern of stopweld material Sandwiched g tgo g gig g g g g within it, with at least a portion of the stop-weld 0 Sea: material corresponding to at least one inflatable fluid 29/ 157.3 V; 113/116 B, 116 Y, 118 A-1l8 D passageway. The apparatus comprises a spindle whose operative surface is contoured to provide the desired [56] References C'ted bend radius. The apparatus further includes means for UNITED STATES PATENTS embossing the strip and means for bending the strip about the spindle. Alternative embodiments include 3,244,130 4/1966 Hipple, Jr ..113/116 B the use f a rubber spindle d combined means for 2,845,695 8/ 1958 Grenell ..29/ 157.3 V bending and embossing the strip 2,514,469 7/1950 Burkhardt ..29/ 157.3 V 3,545,394 12/1970 Shive ..29/157.3 V

11 Claims, 8 Drawing Figures PATENTEDSEP 12 I972 sum 2 or 3 INVENTORI RICHARD A. SH/l E PATENTED SEP 12 1912 SHEET 3 [IF INVENTOR I RICHARD A SH/VE y "(ua ATTORNEY This application is a continuation of U.S. application Ser. No. 823,219, filed Feb. 25, 1969, now abandoned, which in turn is a division of U.S. application Ser. No. 709,636, filed Mar. 1, 1968, nowv U.S. Pat. No. 3,545,394, granted Dec. 8, 1970.

This invention relates to processing metal strip containing stop-weld material which strip is to be subsequently inflated to form passageways. However, this invention could be practiced on flat seam welded passageways or flattened seam, or seamless tubing shipped in coil form, either of which to be inflated after shipping.

It is well known to place a pattern of stop-weld material on one sheet and then by appropriate processing bond the sheet containing the stop-weld material to at least one other sheet at all places except wherethe stop-weld has been placed. After the bonding, the passageway pattern defined by the stop-weld material may be inflated to form passageways.

It is often convenient to inflate such passageways in strip material and to bend the strip material into long serpentine shaped structures which have heat exchange application.

However, ifv a radius below approximately 1 inch is bent, their results kinking in the insideradii of the tube and a reduction in tube height on the outside radii of the tube is evident. This is generally the case in tube wall thicknesses less than 0.030 inches. Kinking is disadvantageous because if the expanded passageways contain kinks, a higher pressure drop occurs.

Furthermore, the kinking may be sufficiently severe to cause failures in the material. For instance, for condenser applications pressures up to 3,000 psi must be tolerated in the passageways. Evaporator or pressures up to 1,200 psi must be tolerated.

Thus, it is an object of the present invention to avoid kinking which often occurs during bending in a conventional fashion.

It is another object of the present invention to avoid kinking when bending strip at a radius of less than 1 inch.

It is another object of this invention to emboss and bend tube wall thicknesses below 0.030 inches without kinking.

It is another object of the present invention to provide a method and apparatus for bending strip to be used in serpentine shaped heat exchangers.

It is another object of this invention to provide a method of bending strip whereby fin material'can be placed between the bent strip and then inflated to form heat exchangers.

Other objects will be apparent from the following descriptions and drawings.

FIG. 1 is a schematic perspective view of the apparatus and process of the present invention.

FIG. 2 is asectional view of the center spindle assembly which is used in the apparatus of the present invention.

FIG. 3 is a perspective view of the movable base plate and divider blocks.

FIG. 4 is a perspective view of the roller assembly.

FIG. 5 is a perspective view of the follower block and pins which may be utilized in the present invention.

. FIG. 6 is a perspective view of strip material which has been bent and formed according to the present invention.

FIG. 7 is a perspective view of strip which has been bent according to the present invention, fin material placed between the strip, and the strip inflated to form a heat exchanger.

FIG. 8 is a schematic view of an exemplary process sequence which may be utilized according to the present invention.

In FIG. 1 there is shown a fixed base plate 10 upon which is mounted a movable base plate 20. Passing through the movable base plate is a center spindle 30. As shown in FIG. 2, this center spindle has an enlarged portion 31 which engages the fixed base plate at 11 by a press fit. Holes 12 are provided for mounting the fixed base plate upon a large table, floor, etc. The movable base plate 20 through opening 21, engages the portion 33 of the center spindle shown with a sliding fit.

A die spindle 40, having grooves 41, 42, 43 and 44 and a shoulder 45 is placed upon the center spindle through center opening 49. It can be seen from FIG. 1 that the center spindle extends above the die spindle,

the upper portion having threads 32. A combination retainer pivot and nut 46 is then screwed onto the threads 32 to hold the die spindle 40 in place.

Mounted on the movable plate 20 is a roller assembly 50. This roller assembly consists of an adjusting bolt 51 contoured at 52 to receive a crescent wrench or other device for rotation. The bolt is threaded at 53.

The threaded portion 53 passes through divider blocks 60 through openings 63 and 64 therein. As shown in FIGS. 1 and 3, the divider blocks are bolted to the rotating base plate, into openings therein with bolts 61. The divider blocks are bolted at 62 to guide top 80 containing a generally elliptical opening 81 therein. There is a corresponding opening 23 in the movable base plate.

The adjusting bolt unthreaded portion 54 also passes into a roller fixture shown in FIG. 4. This roller fixture comprises upper and lower plates 71 and 72 respectively, each having openings 73 and 74 therein. These plates are bolted at 77 (or otherwise attached) to back block 75. Circular end portion 54 of the adjusting bolt fits into opening 76, but opening 76 is made sufficiently large that end portion 54 may be easily removed therefrom.

Mounted between the plates 71 and 72 is a wiper roller 90. A wiper roller pin 91 passes through the center of the wiper roller and into the elliptical openings 81 in the guide top and 23 in the movable base plate. Clearance, for example, about two thousandths of an inch is provided between the guide top and the upper plate 71 and also between the plate 20 and the lower roller fixture plate 72. Also, lubrication is generally provided so that the roller fixture assembly 70 and wiper roller can move back and forth on the plate 20 by rotation of adjusting bolt 50.

Mounted on the base plate 10 is a clamping block shown in detail in FIG. 1. This clamping block is made in two halves, the stationary clamp block 101 and the movable clamp block 102. A socket head cap screw 103 holds the fixed half 10] in place on the fixed base plate 10. Bolt 104 passes through respectively openings 106 and 107. Both the halves contain cooperating resessions 110 and 111 for processing inflated strip.

Follower block 120 shown in FIG. 5 contains a plurality of grooves 121, 122, 123 and 124. There is also provided a recess 125 to fit the shoulder 45 on the die spindle. If desired, both sides of the die spindle may be provided with grooves such as 121a, 122a, 123a and the block reversed to accommodate the number of stop-weld patterns in the strip. In either case, pins 126, 1260, for example, of circular cross section are provided to fit into the grooves, the length of the pins corresponding to the length of the follower block.It should be emphasized, however, that the pins may be of any shape if mating sections are provided on die spindle 40 and follower block 120.

A retainer strap 130 is also provided, having an opening 131 which opening allows placement of the strap upon the nut 46.

After placement of the nut 46 on the die spindle 40, the strap 130 may be placed over shoulder 47 and resting on the die spindle and guide top 80. The opening 131 provides a bearing surface during rotation around the die spindle.

The retainer strap 130 has a second opening 132 through which passes a locking Tee 140. The Tee in engagement fits into an opening 82 in the guide top 80.

Two adjustable screws 150 are also screwed into the threaded holes 24 in the movable plate 20 to regulate the height of strip to be processed in the apparatus.

In operation, a piece of strip S which contains stopweld at appropriate places is fed through clamping block 100 and is placed upon the adjustable screws 150. The height of the adjustable screws 150 is adjusted so that the areas in the strip corresponding to desired passageways which contain stop-weld are in alignment with the pins 126 on 126a or the follower block and the grooves 41-44 on the die spindle. The strip is clamped in the clamping block by tightening bolt 104 at a point whereby the bend will occur at the die spindle at the desired length of the strip. One side of the strip contacts die spindle 40. The follower block 120 and pins are then brought into contact with the other side of the strip. Also, at this point, the retainer strap 130 is engaged upon the die spindle nut 46. The locking Tee 140 is inserted into opening 132 in the retainer strap and into the opening 82 in the guide top.

The adjusting bolt 51 is rotated to urge the wiper block 90 into firm engagement with the follower block. For manual operation, a crescent wrench may be utilized to rotate the adjusting bolt 51, to insure firm engagement of the wiper roller 90 and the follower block 120 with pins l21l24.

At this point, the entire movable assembly is rotated with respect to the fixed plate (clockwise in FIG. 1) around the die spindle 40 for at least 25 and preferably 90 to 360. This, of course, bends the strip. For example, as indicated in FIG. 6, the strip 200 is bent 180. However, it also provides grooves 202 in the strip corresponding to the points on the strip where passageways are to be inflated.

Upon inflation of the passageways, no kinking is observed in any size radiuses including radiuses below 1 inch. FIG. 7 shows the inflated strip, with passageways 302 corresponding to grooves 202 in FIG. 6.

After the strip has been bent, for example, into a serpentine pattern by the bending just described, for many applications it is desirable to braze or otherwise place fin material between the strip. Such fin material is shown at 310 in FIG. 7.

FIG. 8 shows an exemplary strip processing sequence. The previously described bending takes place at schematically shown bending station 400. The strip will leave the bending station 400 and pass to the assembly station 410. At this point, the fin material 411 and end plates 413 and headers 414 are assembled. The fin material and/or the strip will contain a coating of brazing material so that when the strip-fin units 412 are introduced into the furnace 420, which is maintained at the temperature appropriate for the particular brazing alloy, strip material and fin material being processed, the fin material is solidly brazed to the strip.

After the brazing operation, the articles are then moved on to the inflation station 430. At the inflation station at one end of the strip an inflation needle is introduced into the pattern of stop-weld material, and clamped by means of hydraulic line 432. Fluid pressure by means of air line 431 which, for example, supplies water or air, is then introduced into the opening and the passageway pattern is inflated to form passageways corresponding to the passageways of stop-weld material between the sheets. If desired, the inflated articles may be checked for leaks in a water tank 440.

Inflation subsequent to the brazing operation provides very intimate contact between the fin material and the strip so that the brazed fin material is in excellent heat exchange relation with the strip.

It is to be emphasized that the bending according to the present invention need not be used in connection with brazed fin applications only. For example, the strip could be provided with fin area in accordance with Keith application Ser. No. 630,376, assigned to the same assignee as the present application.

It also is to be emphasized that the number of corresponding pins 126 and grooves 41-44 may vary as desired. There have been shown four for purposes of illustration but, if desired one only, or a great many grooves and corresponding pins may be provided in accordance with the number of passageways in this strip.

Other fastening methods, such as welding, could be used instead of screws.

Also, instead of a die spindle, a rubber pad could be used to cooperate with pins 123 or other protrusion.

It is also to be emphasized instead of the follower block, the wiper roller could be contoured so as to contain the equivalent of pins 126 in the follower block. Thus, with this construction, the follower block would be eliminated. Additionally, the embossing and bending could be carried out separately, but it is generally more convenient to carry them out simultaneously.

The bending operation of the present invention may be carried out continuously. This may be done in the following manner.

Strip is fed into the apparatus at a continuous intermittent rate after a desired amount of strip has passed the clamping block. The clamping block may be made to close automatically with an appropriate electro-neumatic time sequence or, the bending and embossing could take place while the strip is moving, Likewise, either the follower block or an appropriately contoured wiper roller may be automatically moved into engagement withthe strip and the die spindle 40. Appropriate electro-neumatic power would then rotate the movable plate around the die spindle.

Such automatic control and time power sequence are well known to those skilled in the metal fabricating field. However, such automatic operation would nonetheless produce bended strip free from kinks, whichis the. essence of the present invention.

It is to be understood that the invention is not limited to the illustrations described and shown herein which are deemed to be merely illustrative of the best modes of carrying'out the invention, and which are susceptible of modifications of form, size, arrangement of parts and detail of operation, but rather is intended to encompass all such modifications which are within the spirit and scope of theinvention as set forth in the appended claims.

What is claimed is:

1. An apparatus for embossing and bending metal strip having a pattern of stop-weld material sandwiched within it, at least a portion of said pattern of stop-weld material corresponding to at least one inflatable fluid passageway, said apparatus comprising:

a spindle whose operative surface is contoured to provide the desired bend radius in said strip, said spindle having at least one groove in its operative surface, said spindle contacting a first surface of said strip so that said portion of said pattern of stop-weld material corresponding to said at least one tubular passageway is in substantial alignment with said at least one groove;

means for embossing and bending said strip about said spindle, the operative surface of said embossing and bending means being contoured to substantially mate with the operative surface of said spindle, said embossing and bending means cooperatively engaging the surface opposing said first surface of said strip so as to emboss and bend said strip about said spindle; and

means operative to move said embossing and bending means about said spindle.

2. An apparatus as in claim 1 further including means for inflating said fluid passageway.

3. An apparatus as in claim 1 which further comprises: a fixed base, said spindle being mounted on said fixed base; and wherein said means for moving said embossing and bending means about said spindle comprises: a moveable plate pivoted about said spindle, said embossing and bending means being mounted on said pivoted plate; whereby said strip is embossed and bent as said plate is pivoted about said spindle.

4. An apparatus as in claim 3 wherein said embossing and bending means comprises: a follower block which engages said strip, the surface of said follower block having protrusions in conformity with the grooves in said spindle; and means for moving said follower block contains a plurality of grooyes.

. n apparatus as in claim 3 wherein said embossing and bending means comprises: a follower block which engages said strip, said follower block having at least one groove; at least one pin having a shape adapted to substantially mate with said at least one groove of said die spindle being mounted within said groove of said follower block; and means for moving said follower block into and out of engagement with said strip and said spindle.

8. An apparatus as in claim 3 wherein said embossing and bending means comprises: a roller which engages said strip and substantially mates with said operative surface of said spindle; and means for moving said roller into and out of engagement with said strip and said spindle.

9. An apparatus for embossing and bending metal strip having a pattern of stop-weld material sandwiched within it, at least a portion of said pattern of stop-weld material corresponding to at least one inflatable fluid passageway, said apparatus comprising:

a spindle comprising a rubber pad, said spindle contacting a first surface of said strip;

means for embossing and bending said strip about said spindle, the operative surface of said embossing and bending means containing at least one protrusion adapted to contact and emboss said strip at said pattern of stop-weld material corresponding to said at least one tubular passageway, said embossing and bending means cooperatively engaging the surface opposing said first surface of said strip so as to emboss and bend said strip about said spindle; and

means operative to move said embossing and bending means about said spindle.

10. An apparatus as in claim 9 further including means for inflating said fluid passageway.

11. An apparatus as in claim 10 wherein said means for embossing and bending said strip contains a plurality of protrusions. 

1. An apparatus for embossing and bending metal strip having a pattern of stop-weld material sandwiched within it, at least a portion of said pattern of stop-weld material corresponding to at least one inflatable fluid passageway, said apparatus comprising: a spindle whose operative surface is contoured to provide the desired bend radius in said strip, said spindle having at least one groove in its operative surface, said spindle contacting a first surface of said sTrip so that said portion of said pattern of stop-weld material corresponding to said at least one tubular passageway is in substantial alignment with said at least one groove; means for embossing and bending said strip about said spindle, the operative surface of said embossing and bending means being contoured to substantially mate with the operative surface of said spindle, said embossing and bending means cooperatively engaging the surface opposing said first surface of said strip so as to emboss and bend said strip about said spindle; and means operative to move said embossing and bending means about said spindle.
 2. An apparatus as in claim 1 further including means for inflating said fluid passageway.
 3. An apparatus as in claim 1 which further comprises: a fixed base, said spindle being mounted on said fixed base; and wherein said means for moving said embossing and bending means about said spindle comprises: a moveable plate pivoted about said spindle, said embossing and bending means being mounted on said pivoted plate; whereby said strip is embossed and bent as said plate is pivoted about said spindle.
 4. An apparatus as in claim 3 wherein said embossing and bending means comprises: a follower block which engages said strip, the surface of said follower block having protrusions in conformity with the grooves in said spindle; and means for moving said follower block into and out of engagement with said strip and said spindle.
 5. An apparatus as in claim 4 which further includes means contacting said strip for aligning said strip, so that said stop-weld pattern corresponding to said at least one tubular passageway is in alignment with said at least one groove in said spindle.
 6. An apparatus as in claim 5 wherein said spindle contains a plurality of grooves.
 7. An apparatus as in claim 3 wherein said embossing and bending means comprises: a follower block which engages said strip, said follower block having at least one groove; at least one pin having a shape adapted to substantially mate with said at least one groove of said die spindle being mounted within said groove of said follower block; and means for moving said follower block into and out of engagement with said strip and said spindle.
 8. An apparatus as in claim 3 wherein said embossing and bending means comprises: a roller which engages said strip and substantially mates with said operative surface of said spindle; and means for moving said roller into and out of engagement with said strip and said spindle.
 9. An apparatus for embossing and bending metal strip having a pattern of stop-weld material sandwiched within it, at least a portion of said pattern of stop-weld material corresponding to at least one inflatable fluid passageway, said apparatus comprising: a spindle comprising a rubber pad, said spindle contacting a first surface of said strip; means for embossing and bending said strip about said spindle, the operative surface of said embossing and bending means containing at least one protrusion adapted to contact and emboss said strip at said pattern of stop-weld material corresponding to said at least one tubular passageway, said embossing and bending means cooperatively engaging the surface opposing said first surface of said strip so as to emboss and bend said strip about said spindle; and means operative to move said embossing and bending means about said spindle.
 10. An apparatus as in claim 9 further including means for inflating said fluid passageway.
 11. An apparatus as in claim 10 wherein said means for embossing and bending said strip contains a plurality of protrusions. 